U.S. Pat. No. 4,459,959 issued to Terada et al. on Jul. 17, 1984 and U.S. Pat. No. 4,372,272 issued to Walter et al. on Feb. 8, 1983 disclose hydraulically-actuated unit injector fuel systems.
Hydraulically-actuated unit injector fuel systems, having multiple manifolds for supplying high pressure actuating fluid to the unit injectors, can create a Helmholtz resonance effect between the manifolds. The Helmholtz resonance effect is caused by high pressure pressure waves that reflect back and forth between the manifolds which are supplied by a common high pressure pump. The pressure waves are created as a result of a temporary loss of pressure in one of the manifolds when a unit injector, communicating with that manifold, has used actuating fluid in order to effect fuel injection. The creation of a Helmholtz resonance effect between the manifolds causes the manifold pressures to be nonuniform which then interferes with the intended sequence of fuel injections by the unit injectors.
The present invention is directed to overcoming one or more of the problems as set forth above.